Hydraulic transmission



June 1951 G. H. SNYDER HYDRAULIC TRANSMISSION 4 Sheets-Sheet 1 FiledMarch 23, 1948 INVENTOR. GEORGE H. SNYDER,

H BY

A TTONEY$ G. H. SNYDER HYDRAULIC TRANSMISSION June 12, 195] 4Sheets-Sheet 2 Filed March 25, 1948 INVENTOR.

ATTORNEYS,

June 12, 1951 G; H. SNYDER 2,556,656

HYDRAULIC TRANSMISSION I Filed March 23, 1948 4 Sheets-Sheet 5 FIG. 7.

JNVENTOR. GEORGE H. SNYDER,

ATTORNEYS.

Patented June 12, 1951 UNITED STATES PATENT OFFICE HYDRAULICTRANSMISSION George H. Snyder, Toledo, Ohio Application March 23, 1948,Serial No. 16,605

7 Claims. 1

My invention relates to means for transmitting power hydraulically froma drive to a driven shaft, and relates more particularly to thetransmission of power from the hydraulic coupling interposed between aninternal combustion engine and the running gear of a motor vehicle.Obviously, the device of the invention is not so limited, however.Specifically, the invention relates to a hydraulic coupling wherein abody of hydraulic driving fluid is confined in a hollow driving rotorwithin a stationary housing, and which driving rotor is adapted to berotated by the drive shaft of the engine. Rotation of such rotor createscentrifugal force which positions the body of hydraulic fluid in anannularlyshaped formation against the peripheral wall of the rotor. Adriven rotor is positioned concentrically within the driving rotor andprovided with vanes projectible into and out of the annularly-shapedformation of rotating hydraulic fluid, whereby to couple the drivingrotor to the driven rotor.

With the foregoing in view, it is an object of my invention to providean improved hydraulic transmission of the class described.

A further object of the invention is to provide an improved hydraulictransmission of the class described which includes means for selectivelyreversing the direction of rotation of the driven rotor withoutreversing the direction of rotation of the driving rotor.

A further object is to provide an improved hydraulic transmission of theclass described together with means automatically coupling the drivenshaft to a load at a reduction gear ratio during initial rotation of thedriven shaft, and thereafter automatically coupling the driven shaftdirectly to the load when the speed of rotation of the driving rotorreaches a predetermined rate.

A further object is to provide a novel transfer case for a hydraulictransmission which includes means for automatically connecting a drivenshaft to a take-off shaft by either reduction gearing or by a directconnection in accordance with the speed of rotation of the drivingrotor.

A further object is to provide an improved hydraulic transmission whichincludes means for selectively operating a driven shaft in oppositedirections without reversing the direction of rotation of the driveshaft, and which includes novel valve means for controlling thedirection of rotation of the driven shaft.

Other objects and advantages reside in the particular structure of theinvention, the structure of the elements forming the same, combinationand arrangement of the several elements thereof, and/or in theparticular method or mode of operation, all of which will be readilyapparent to those skilled in the art upon reference to the attacheddrawings in connection with the following specification, wherein theinvention is shown, described and claimed.

In the drawings:

Figure 1 is a longitudinal vertical section through a preferred form ofthe transmission according to the invention;

Figure 2 is a transverse vertical section of the same;

Figure 3 is an elevational view of the same, parts being broken away toshow interior parts more clearly;

Figure 4 is an enlarged fragmentary vertical sectional view takensubstantially on the plane of the line 4-4 of Figure 1;

Figure 5 is a vertical sectional view taken substantially on the planeof the line 55 of Figure 4;

Figure 6 is an enlarged perspective view showing a detail apart from therest of the structure;

Figure 7 is an end elevational view, parts being broken away and shownin longitudinal vertical section and showing certain of the parts in adifferent position from that shown in Figure 1;

Figure 8 is an enlarged perspective view, parts being broken away andshown in section, of an element of the invention apart from the rest ofthe structure;

Figure 9 is a longitudinal vertical sectional view like Figure 1, butshowing a slightly modified structure of the invention.

. Referring more specifically to the drawings, wherein like referencecharacters have been used throughout the several views to designate likeparts, and referring particularly to that form of the inventionillustrated in Figures 1 to 8, inclusive, Ill designates any suitabledrive shaft adapted to be rotated by any suitable source of power, notshown. The drive shaft I0 is journaled in a hub H of a housing-providingmember I2 which is secured to an opposed and complementaryhousing-providing member I3 by any suitable means l4 extending throughperipherally-disposed flanges thereof. Such members !2 and I3 areprovided with plugs 5 at the upper ends to permit the introduction offluid to the interior of the housing, and at least one of the housingsmay be provided with a suitable drain plug I6. The shaft ID is journaledin the hub I I for rotation relative thereto by any suitable bearing 3means il, and any suitable packing I8 is provided to form a fluid-tightjoint about the shaft 10. The housing-providing member i3 is likewiseprovided with a hub l9 in which is journaled a driven shaft 253. Thedriven shaft 28 is journaled for rotation relative to the housing l2 and13 by any suitable bearings ii, and suitable packing i8 provides afluid-tight seal along such driven shaft. It is to be understood thatthe housing formed by the members 12 and i3 is fixed to any suitablesupport, not shown, such as the frame of an automobile. The driven shaft20 is connected to any suitable load, such as the running gear, notshown, of the automobile.

The drive shaft iii has fixed on the inner end or formed on the innerend a driving rotor 21 which comprises a closed casing having a radiallyoutwardly-directed web 22 which merges into a preferably concavoconvex,circumferential wall 23, which, in turn, merges into aninwardly-directed web 24 parallel to the web 22. The inner ends of theweb 24 are journaled on the driven spaces 26 and a peripheral space 25therebetween.

The drive shaft ii] is provided with an axial bore 27, while the innerend of the driven shaft 23 is likewise provided with an axial bore 28.Such bores 2'5 and 28 are preferably of the same diameter and shape andare coaxial. shaft I is provided with a plurality of intake ports 29extending therethrough and communicating with the bore 27. In likemanner, the driven shaft is provided with a plurality of intake ports 35communicating with th bore 23 thereof. Thus, fluid in the lateral spaces26 may be passed therefrom into the bores 28 and 27 of the shafts.

The peripheral wall of the driving rotor 2! is provided with a pluralityof radially inwardlydirected and fixed baffles 31, each of which isformed with an opening 32 therethrough. The baflles 3! arecircumferentially spaced around the rotor 21 and extend inwardly arelatively short distance to provide a space 33 axially inwardlythereof. The peripheral wall is likewise provided with a plurality ofdischarge ports 34 between adjacent bafiles 31 which discharge into theperipheral space 2.5 of the housing. The outer surface of the peripheralwall 23 is provided with a plurality of concave fixed baffles 35 whichdirect fluid passing through the ports 34 laterally in both directionsinto the lateral spaces 26 of the housing. In this connection, it shouldbe noted that the driving rotor 2! is adapted to contain a body ofhydraulic driving fluid, not shown. Upon rotation of the driving rotorwith the drive shaft [8, such body of fluid assumes an annular formationagainst the peripheral wall 23 and extends into the space 33 aforesaid.The openings 32 in the baffies 3i serve to equalize pressure in thefluid, while the baffles 31 cause the fluid to rotate with the drivingrotor 29. Obviously, the centrifugal force generated causes portions ofthe body of fluid to escape through the discharge ports 34 outwardly ofthe driving rotor. The bafiles 35 direct the escaping fluid laterally inboth directions into the spaces 25 and to the intake ports 29 and 38 inthe driving and driven shafts Ill and 28, respectively.

The drive The driven shaft 25 has fixed on the end thereof a drivenrotor which is generally indicated by 40, and which includes a centralweb formed with a plurality of radially outwardly-extending cylinders4!, The cylinders 4| communicate with the bore 28 of the driven shaft 25by forward ports 42. A piston 43 is slidable in each cylinder 4i andincludes an outwardly-directed stem 44 terininating in a vane 45. Thestem 44 may be detachably connected to the piston 43 by any suitablemeans, such as the threaded connection 4'1, Figure 6. Likewise, the stem44 is preferably of angular configuration, whereby to prevent turning ofthe same in the slot 48 which slidably receives the stem and the vanes45. A coil spring 46 is positioned in each cylinder 4! and isconcentrically disposed about the stem 44. One end of each spring bearson the outer surface of the piston 43, while the opposite end bearsagainst the closed outer end of the cylinder, whereby the piston 43 isloaded for radial inward movement toward the port 42. With thetransmission parts at rest, the springs 45 retract the pistons 43 andvanes 35 to the innermost limit of the cylinders 4|, as shown inFigure 1. In this position, the outer end edges of the vanes 45 areflush with the outer periphery of the driven rotor 40, and no rotationis imparted to the driven rotor 49 upon initial rotation of the drivingrotor 2|. However, upon continued rotation of the driving rotor 2|,driving fluid is forced through the ports 29 and 30 into the bore 28 ofthe driven shaft 20, and from there radially outwardly through theforward ports 42 into the cylinders 4|. Continued rotation drives thepistons 43 radially outwardly and into the space 33 between the outerperiphery of the driven rotor and the inner edges of the baffles 3 I.The faster the driving rotor is rotated, the further the vanes 45 areprojected outwardly until they reach a limit of outward travel best seenin Figures 4 and 5, wherein the outer edges of the vanes 45 are justclear of the imier edges of the fixed baffles 3!. Continued rotation ofthe driving rotor, together with the fluid body contained therein, iseffective to operatively couple the driving rotor to the driven rotor ina well known manner. Thus, rotation is imparted to the driven shaft 29in the same direction as that in which the drive shaft ill is rotating.Likewise, there is a direct relation between the speed of rotation ofthe driving rotor and that imparted to the driven rotor. For instance,with the driving rotor rotating at relatively low speeds, substantiallylittle pressure will be exerted on the pistons 43, whereby the vanes 45are projected but a short distance into the space 33. Thus, a lesspowerful coupling is achieved and the speed of rotation of the drivenshaft 28 is relatively slow. However, upon maximum speeds and with thevanes 45 fully projected, a substantially direct coupling is achieved,whereby the driving and driven rotors, together with their shafts, arer0- tating at substantially the same speed.

As so far described, the driven rotor is capable of rotation only in thesame direction as that of the driving rotor. However, means now to bedescribed permit reversing of the driven rotor and its related shaftwithout reversing the direction of rotation of the driving rotor anddrive shaft. Such reverse movement is accomplished by providing aplurality of radially-extending and laterally oppositely-directedreversing vanes 55, Figure 3, on opposite sides of the web providing thecylinders for the driving rotor 40. Such vanes 50 diverge radiallyoutwardly in a well known manner and may be curved to achieve the mostdesirable results, as shown in Figure 3. The driven shaft is providedwith a pluralit of radially outwardly-directed reversing ports 5| whichprovide communication between the bore 28 of the driven shaft and theinterstices between each reversing blade 50. Obviously, it is desirableto maintain the reversing ports 5| closed while the forward ports 32 areopen, and vice versa. To accomplish this purpose, I have provided aslide valve 52 which is slidable in the aligned bores 28 and 2! of thedriving and driven shafts II] and 20, respectively. Such slide valve 52is best illustrated in Figure 8, and comprises a stem 53 which extendsaxially outwardly of the bore 28 in a counterbore 54'of the driven shaft20. Such counterbore terminates in a cross-slot 55 in the driven shaftto permit coupling of the stem 53 of the valve to a collar 56 in a wellknown manner. The collar 56 is provided with an annular groove forconnection to any suitable actuating yoke, not shown. Thus, the slidevalve 52 may be reciprocated in the aligned bores 21 and 28, while theshafts are rotating or relatively rotating.

The valve 52 is cylindrical in form and has a close fit in the alignedbores aforesaid. Likewise, the end portions of the valve are providedwith longitudinally-spaced annular grooves 53,

each of which has formed in the floor thereof a radiallyinwardly-directed inlet port 51. Such ports open into alongitudinally-extending bore 60 formed in the valve 52. Intermediatethe grooves 58, the periphery of the valve 52 is formed with a secondand smaller groove 62 into the floor of which opens an outlet port 6|which establishes communication between the groove 62 and the bore 60 ofthe valve. An additional annular groove 58 is formed in the valve 52between one of the grooves 58 and the groove 62 for a purpose to bedescribed.

Figure 1 shows the valve 52 disposed for forward movement of the drivenrotor 43, and in this position, the grooves 58 are disposed below theinlet ports 29 and in the drive shaft l0 and the driven shaft 29,respectively. Likewise, the intermediate groove 62 is aligned with theforward ports 42 opening into the cylinders ti. Thus, fluid forced downthe lateral spaces 28 passes through the ports 29 and 30, into thegrooves 58 and ports 51 of the valve along the axial bore Gil thereofand outwardly through the discharge ports 6| into the cylinders 4|,whereby to actuate the pistons 43 and the vanes 45, as previouslydescribed. to cause the driven rotor 49 to rotate in a directionopposite to that of the direction of rotation of the driving rotor, thevalve 52 is moved to the position shown in Figure '7. In this position,the left-hand end groove 58 and the groove 58' of the valve 52 bridgethe ports 29 and 30 and the adjacent reversing ports 5|. At the sametime. the intermediate groove 62 is moved out of registry with theforward ports 62, whereby the pistons 43 remain retracted. Meanwhile,fluid under pressure passing through the reversing ports 55 engages thereversing vanes 58 and is effective to rotate the driven rotor ii! in adirection opposite to the direction of rotation of driving rotor 2|After clearing reversing vanes 56. the fluid is discharged radiallyoutwardly into space 33 and rejoins the rotating annular body of fluidcontained therein.

Referring now to Figure 9, a slightly modified structure is theredisclosed. However, it is to When it is desired 6 be understood that thedriving and driven ro tors 2| and Gil, respectively, are the same aspreviously described. In this construction, .a drive shaft IQ isconnected to a suitable source of power, not shown, and is journaled, asat T3, in a wall of a housing 1!. The housing '-'I may contain aflywheel l2 fixed to the shaft 10. An inner end of the shaft ii! isjournaled', as at M, in a hub 15 of a fixed housing l5 which correspondsto the fixed housing 12, I3 of the first-described form of invention.The inner end of the drive shaft H1 is fixed to the driving rotor 3|,and such inner end is provided with an axial bore receiving a bearing T7of any suitable form to provide a journaled connection with the free endof a driven shaft 18. The driven shaft 1-8 is provided with an axialbore 13 in which the slide valve 52 is slidable, as previouslydescribed. However, in View of the fact that the driven shaft 13 istelescoped within the inner end of the drive shaft '10, an additionalintake port 89 is provided to align with the intake port 29 of the driveshaft. Fluid is circulated through the device, and the direction ofrotation of the driven rotor 4|! is controlled in the same manner as inthe first-described form of the invention. The outer end of the drivenshaft 78 extends into a transfer case 8| which is fixed to thehousing-providing portion 82 substantially concentrically of the drivenshaft. The transfer case 8| has journaled therein a take-off shaft 83which is preferably axially aligned with the driven shaft 18.Preferably, an inner end 84 is telescopically received in a recessformed in the outer end of the driven shaft 78 to provide a journal. Theouter end 85 of the take-off shaft 33 extends outwardly of the transfercase 8| and is adapted for connection to any suitable load, not shown.The transfer case 8| contains a counter-shaft 85, the ends of which arejournaled in the transfer case in any suitable bearings. Thecountershaft 85 has fixed thereon in spaced relation a pair ofspeed-reducing gears 8-? and 38. A pinion 85 is fixed on the end of thedriven shaft I8 for rotation therewith and is in constantmesh with thereduction gear 81. The outer end surface of the pinion 89 is formed toprovide clutch teeth 9!! for a purpose to be described later. Outwardlyof the pinion 89, an idler pinion 9| is journaled for free rotation onthe take-off shaft 83 by any suitable bearings. The inner lateral faceof the idler pinion 9| is provided with clutch teeth 92. The idler gear9| is in constant mesh with the s cond reduction gear 88. Intermediatethe pinions 89 and 9|, the take-off shaft 83 is splined longitudinally,as at 93, for slidable and rotatable engagement with a double-facedclutch member 94. The clutch member 5 1 is a double-faced clutch memberprovided with laterally inwardly and outwardly-directed clutch teeth and96, respectively, which are complementary to the clutch teeth 9!) and92, respectively, of the driven pinion 89 and idler pinion 9|. Theclutch 94 rotates with the take-off shaft 83. The outer periphery of theclutch 94 is formed with an annular groove 9! for engagement with a yoke98 adapted to slide the clutch 94 backward and forward on the splinedportion 93 of the takeoff shaft 83. The upper end of the yoke 98 isslidable on a guide 99 Which extends longitudinally of the transfer case3| in parallel relation to the shafts l8 and 83. The guide 99 likewisesupports in fixed relation thereto a cylinder I00 in which is slidable apiston NH. The piston I! includes a stem I92 which extends through anend wall of the cylinder I01] and is fixedly connected in any suitablemanner to the yoke 98. Inasmuch as the cylinder N13 is parallel to theshafts l8 and 83, actuation of the piston will serve to actuate theclutch 34 in opposite directions on the splined portion 93 of thetake-off shaft 83. A spring E33 is positioned in the cylinder 166between the inner end surface of the piston H3! and the inner end of thecylinder. Thus, the piston lill and the clutch 94 are normallypositioned outwardly under the load of the spring 103 so that the outerclutch teeth 96 of the clutch are operatively engaged with theinwardly-directed clutch teeth 92 of the idler pinion 9|. Thus, with thedriven rotor 40 actuating as previously described, power is transmittedto the take-01f shaft 83 through the driven shaft 78, driven pinion 89,reduction pinions 8'! and 88, the idler pinion 9!, clutch 9:3, splines93 to the take-off shaft 83. Obviously, by virtue of the reductiongearing, substantially little power is required to turn the take-offshaft 83 with this arrangement. Thus, the initial actuation of thedriven rotor is relatively easy. To engage the inner clutch teeth 95 ofthe clutch 94 with the driven pinion 89, there has been provided apressure conduit IE4 which extends from one lateral space 26 in thehousing 76, 82 to the outer end of the cylinder I99. Thus, whensufiicient fluid pressure has been generated in such space 26, fluidunder pressure passes through the conduit I04 to the outer end of thecylinder I00 and moves the piston Hli inwardly in such cylinder againstthe action of the spring I03. Such movement takes with it the yoke 93and clutch 94, whereby the clutch teeth 95 are engaged with the clutchteeth 90 of the driven pinion 89 after disengagement of the outer clutchteeth 96 from the idler pinion 9!. The arrangement thus describedprovides a direct connection between the driven shaft '58 and thetake-off shaft 83. This is obviously the case as the speed-reducinggearing 81 and 83 are now connected only to the idler pinion 9!, which,as aforesaid, is freely rotatable on the take-off shaft 83.

The arrangement just described provides means automatically connectingthe driven shaft and take-off shaft for direct drive after sufficientspeed has been picked up by the driving rotor 2|. That is to say, whensufiicient speed has been generated by the driving rotor, sumcientpressure will have been generated in the space 26 aforesaid to actuatethe piston IOI Moreover, this is true irrespective of whether the valve52 is positioned for forward or reverse drive.

It is to be understood that the particular forms of the invention shownand described hereinabove are susceptible of changes in arrangement,location of parts, whereby to carry the several functions statedhereinabove. Likewise, while I have shown and described what is nowthought to be the preferred embodiments of the invention, it isunderstood that the same is susceptible of other forms and expressions.Consequently, I do not limit myself to the precise structures shown anddescribed hereinabove, except as hereinafter claimed.

I claim:

1. A hydraulic transmission, comprising a fixed housing, a drive shaftand a driven shaft, said shafts being axially aligned and includingadjacent free ends journaled in said housing and extending inwardlythereof, each of said free ends being formed with an axial bore, ahollow driving rotor fixed to said drive shaft inwardly of said housingand spaced therefrom, said rotor being adapted to contain a body ofhydraulic driving fluid therein, a driven rotor fixed to said drivenshaft inwardly of said driving rotor, said driving rotor being formedwith discharge ports discharging radially therefrom into said housing,said free ends of said shafts being formed with intake ports discharginginto said bores from said housing, said driven rotor including aplurality of radially-directed cylinders, a piston in each cylinder, avane fixed to each piston and movable radially therewith into and out ofdriving engagement with said fluid to couple said driven rotor and shaftto said driving rotor for rotation therewith, laterally-directed fixedreversing vanes on said driven ro tor, a slide valve in said bores ofsaid shafts, said bore of said driven shaft includinglongitudinally-spaced forward and reversing ports dischargingrespectively to said cylinders and reversing vanes, and means for movingsaid slide valve to selectively open and close said forward andreversing ports whereby to selectively actuate said driven shaft inopposite directions,

2. A hydraulic transmission, comprising a fixed housing, a drive shaftand a driven shaft, said shafts being axially aligned and includingadjacent free ends journaled in said housing and extending inwardlythereof, each of said free ends being formed with an axial bore, ahollow driving rotor fixed to said drive shaft inwardly of said housingand spaced therefrom, said rotor being adapted to contain a body ofhydraulic driving fluid therein, a driven rotor fixed to said drivenshaft inwardly of said driving rotor, said driving rotor being formedwith discharge ports discharging radially therefrom into said housing,said free ends of said shafts being formed with intake ports discharginginto said bores from said housing, said driven rotor including aplurality of radially-directed cylinders, a piston in each cylinder, avane fixed to each piston and movable radially therewith into and out ofdriving engagement with said fluid to couple said driven rotor and shaftto said driving rotor for rotation therewith, spring means in saidcylinders loading said pistons and vanes to retracted positions,laterally-directed fixed reversing vanes on said driven rotor, a slidevalve in said bores of said shafts, said bore of said driven shaftincluding longitudinally-spaced forward and reversing ports dischargingrespectively to said cylinders and reversing vanes, and means for movingsaid slide valve to selectively open and close said forward andreversing ports whereby to selectively actuate said driven shaft inopposite directions. 3. A hydraulic transmission, comprising a fixedhousing, a drive shaft and a driven shaft, said shafts being axiallyaligned and including adjacent free ends journaled in said housing andextending inwardly thereof, each of said free ends being formed with anaxial bore, a hollow driving rotor fixed to said drive shaft inwardly ofsaid housing and spaced therefrom, laterally and peripherally to providelateral and peripheral spaces therebetween, said rotor including apcripheral wall formed with a plurality of fixed and relatively shortbafiies extending radially inwardly thereof within said rotor to definea cylindrical space in said rotor axially thereof,

asta

said baflles being formed with openings therein, said rotor beingadapted to contain a body of driving fluid therein, said peripheral wallbeing formed with fluid-discharge ports therein intermediate adjacentbaffles, said ports discharging into said peripheral space, a drivenrotor fixed to said driven shaft inwardly. of said driving rotor inradially inwardly-spaced relation to said baffies, said free ends ofsaid shafts being formed with fluid intake ports discharging into saidbores from said lateral spaces, said driven rotor including a pluralityof radially-directed cylinders, a piston in each cylinder, a vane fixedto each piston and movable radially therewith toward and away from saidbaffles for driving engagement with said body of fluid, fixedradiallyextending reversing vanes projecting laterally of said drivenrotor, forward and reversing ports in said driven shaft for directingfluid from the bore thereof to said cylinders and reversing vanes,respectively, and valve means in said bore of said driven shaft forselectively opening and closing said forward and reversing ports,whereby to actuate said driven shaft selectively in opposite directions.

4. A hydraulic transmission, comprising a fixed housing, a drive shaftand a driven shaft, said shafts being axially aligned and including adjacent free ends journaled in said housing and extending inwardly thereof,each of said free ends being formed with an axial bore, a hollow drivingrotor fixed to said drive shaft inwardly of said housing and spacedtherefrom, laterally and peripherally to provide lateral and peripheralspaces therebetween, said rotor including a peripheral wall formed witha plurality of fixed and relatively short baffles extending radiallyinwardly thereof within said rotor to define a cylindrical space in saidrotor axially thereof, said bailies being formed with openings therein,said rotor being adapted to contain a body of driving fluid therein,said peripheral wall being formed with fluid-discharge ports thereinintermediate adjacent bafiles, said ports discharging into saidperipheral space, baffles fixed to said wall outwardly thereof anddirecting fluid from said ports laterally therefrom in oppositedirections toward said lateral spaces, a driven rotor fixed to saiddriven shaft inwardly of said driving rotor in radially inwardly-spacedrelation to said baffles, said free ends of said shafts being formedwith fluid intake ports discharging into said bores from said lateralspaces, said driven rotor including a plurality of radially-directedcylinders, a piston in each cylinder, a vane fixed to each piston andmovable radially therewith toward and away from said baffles for drivingengagement with said body of fluid, fixed radially-extending reversingvanes projecting laterally of said driven rotor, forward and reversingports in said driven shaft for directing fluid from the bore thereof tosaid cylinders and reversing vanes, respectively, and valve means insaid bore of said driven shaft for selectively opening and closing saidforward and reversing ports, whereby to actuate said driven shaftselectively in opposite directions. V

5. A hydraulic transmission, comprising a fixed housing, a drive shaftand a driven shaft journaled in said housing, a hollow driving rotorfixed to said drive shaft inwardly of said housing, said rotor beingadapted to contain a body of hydraulic driving iiuid therein, a drivenrotor fixed to said driven shaft inwardly of said driving rotor, saiddriving rotor being formed with at least one discharge port opening intosaid housing and adapted to discharge fluid into said housing bycentrifugal force upon rotation of said driving rotor, said driven rotorincluding a plurality of radially-directed cylinders, a piston in eachcylinder, a vane fixed to each piston and movable radially therewithinto and out of driving engagement with said fluid to couple said drivenrotor and shaft to said driving rotor for rotation therewith, fixedreversing vanes on said driven rotor, at least one of said shafts beingformed with an intake port opening into said housing and separateforward and reverse discharge ports in communication with said inletport and discharging respectively into said cylinders and into saidreversing vanes, and means for selectively opening and closing saiddischarge ports whereby to actuate said driven rotor selectively inopposite directions.

6. A hydraulic transmission, comprising a fixed housing, a drive shaftand a driven shaft journaled in said housing, a hollow driving rotorfixed to said drive shaft inwardly of said housing, said rotor beingadapted to contain a body of hydraulic driving fluid therein, a drivenrotor fixed to said driven shaft inwardly of said driving rotor, saiddriving rotor being formed with at least one discharge port opening intosaid housing and adapted to discharge fluid into said housing bycentrifugal force upon rotation of said driving rotor, said driven rotorincluding a plurality of radially-directed cylinders, a piston in eachcylinder, a vane fixed to each piston and movable radially therewithinto and out of driving engagement with said fluid to couple said drivenrotor and shaft to said driving rotor for rotation therewith, springmeans in said cylinders loading said pistons and vanes to retractedpositions wherein said vanes are out of driving engagement with saidfluid, laterallydirected fixed reversing vanes on said driven rotor, atleast one of said shafts being formed with an intake port opening intosaid housing and separate forward and reversing discharge ports incommunication with said inlet port and discharging respectively intosaid cylinders and to said reversing vanes, and means for selectivelyopening and closing said discharge ports whereby to actuate said drivenrotor selectively in opposite directions.

7. The combination including a relatively stationary housing containinga fluid, driving and driven rotors rotatably mounted within the housingand coupled together through the fluid, the fluid creating a pressurewithin the housing proportional to the speed of rotation of the drivingrotor, a driven shaft connected with the driven rotor for rotationtherewith and including a driving gear, a separate power take-oil shaftrotatably supported near the driven shaft, an idler gear freelyrotatably mounted upon the power take-off shaft, a shiftable clutchelement connected with the power take-oil shaft for rotation therewithand engageable with the driving gear and idler gear, a countershaftfreely rotatably supported near the driven and power take-cff shafts,first and second reduction gears secured to the countershaft forrotation therewith and meshing with the drive and idler gearsrespectively, a cylinder disposed near the power take-off shaft andconnected with the housing and having an opening, there being adischarge opening in the housing, conduit means connecting the openingof the housing with the opening of the cylinder, piston means mountedwithin 11 the cylinder and connected with the clutch element forshifting the same into engagement with either of the driving or idlergears, and resilient means connected with the piston means for shiftingit in a direction to hold the clutch eleagent in engagement with theidler gear, the piston means and clutch element shifting against theaction of the spring means when the fluid ithin the housing creates apredetermined pressure so that the clutch will engage the driving gearfor coupling the driven and power take-off shafts directly.

GEORGE H. SNYDER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 895,491 Nash Aug. 11, 19081,095,132 Thomson Apr. 28, 1914 2,006,136 Grimsley June 25, 19352,212,772 Guyer Aug. 27, 1940 2,400,186 Armentrout Mar. 14, 1946

